Automatic bag opening machine



April 1, 1958 1.. B. DOWTY ETAL 2,828,596

AUTOMATIC BAG OPENING MACHINE Filed March 9, 1954 3 Sheets-Sheet 1 LY) 06W?- J 55 J0 wT gfiafai/ eavzkg A ril 1, 1958 L. B. DOWTY ETAL AUTOMATIC BAG OPENING MACHINE 5 Sheets-Sheet 2 Filed March 9, 1954 fizz 612275345.- jee j 0647 eazmwcflffi eavzm jM/ W M QR A ril 1, 1958 1.. B. DOW TY ETAL AUTOMATIC BAG OPENING MACHINE 3 Sheets-Sheet 3 jzvaiz'zor' a. ,Zeejjow fi Filed March 9, 1954 Unite States Patent 2,828,596 AUTQMATIC BAG OPENING MACHltNE Application March 9, 1954, Serial No. 415,636 10 Claims. (Cl. 53-386) This invention relates to a new and improved bag opening machine, and more particularly to a machine which automatically takes a bag from a supply pile or pick-up station, partially opens the top of the bag, and presents it to an operator or to another machine for filling.

Bags in which grain, flour, sugar, chemicals, or other similar products are to be placed for storage or transportation are generally made of paper or relatively tightly woven fabric. Such materials are usually thin and easily folded. Accordingly, as the bags are received from the supplier the opposite sides of each bag are ordinarily folded quite closely together. This frequently causes difiiculty in getting the bag open quickly so that it may be filled as one of a series of bags in a continuous, fastmoving production line.

When opened manually, the bags are usually opened in two steps which are performed simultaneously by two different persons on successive bags. In the first step, one worker takes a bag from the supply pile, opens it slightly, and passes it on to another man. In the second step, the other employee opens the bag further whatever amount is necessary and puts it in place for filling.

It will be seen that the job performed by the worker carrying out the first step of picking up a bag, opening it slightly, and passing it on to the second man is a tedious and monotonous operation. This has made it difficult to get reliable employees for the job. In addition, of course, the hiring of two men increases labor costs.

This invention eliminates the necessity for the first man. The invention not only performs the function now carried out by that employee, but does it more speedily and with more uniform results than the human worker is able to do.

The invention will be described in relation to the embodiment shown in the accompanying drawings. In the drawings:

Figure l is a side elevation of a bag opening machine which is one embodiment of this invention;

Figure 2 is a plan view of the same embodiment;

Figure 3 is an enlarged fragmentary plan view showing details of a part of the machine; and

Figure 4 is a sectional view taken along line 4-4 in Figure 3.

Bag cnvey0r.-In Figure 1, bag conveyor 6 includes frame 7, pulley wheels 8, and conveyor belts 9 upon the pulley wheels. A supply of bags 10 rests upon the conveyor belts.

Guide gears 11 and chain belts 11a help provide support for bags 10 at their upper ends, and help to move the bags forward toward the feeding station as described below.

Drive for c0nvey0r.-Air cylinder 13 provides the main motive power for bag conveyor 6. When the cylinder is actuated as described below, piston rod 14 moves arm 15 which is connected with pulley wheel 8 seen at the left in Figure 1 by means of a pawl 16 and ratchet wheel 17. Pawl 16 is seen in dotted lines in Figure 2.

When arm 15 is moved upward by upward motion of piston rod 14, pawl 16 engages in ratchet wheel 17. This causes front pulley wheels 8 to rotate so that conveyor belts 9 move to the left in Figure 1. When arm 15 is moved in a downward direction, there is no engagement between the pawl and ratchet whee From Figures 1 and 2 it is seen how bags 10 are moved forward on conveyor belts 9 until the most forward bag strikes microswitch 18. This switch is normally closed, and is opened by pressure exerted by a bag arriving at the feeding station. The switch is connected in the actuating circuit for air cylinder 13 as described below.

Auxiliary motive power for bag conveyor 6 is provided by electric motor 12 positioned at the bottom of the conveyor. Through a system of gears and chains 12a, motor 12 causes guide gears 11 on opposite sides of bag conveyor 6 to rotate in opposite directions. Chain belts 11a are so disposed that they exert some slight transverse pressure on the sides of bags 10 near the top of the bags. Thus, when the chain belts are moved by the rotation of guide gears 11, they help to move the supply of bags forward toward the feeding station.

Normally closed microswitch 126 is connected in series with the actuating circuit of electric motor 12. It is located, as shown in Figure 1, at the front of the bag conveyor near the feeding station. Pressure of a bag at the feeding station on the microswitch breaks the actuating circuit for motor 12.

Suction cup.-The bag opening mechanism itself is supported on a forward extension 19 of frame 7. Riser 26 carries switch box 21 and, at its top, movable arm 22. Arm 22 is connected at one end with the reciprocating piston in air cylinder 23 and at the other end through a system of gears with suction cup 24. The piston forms a hermetic barrier in cylinder 23.

Suction cup 24 is connected through vacuum line 25 to vacuum pump 26, which is driven by electric motor 27. Power is supplied to motor 27 through main supply line 23, junction box 29, and line 30, 31 is closed.

Suction cup arm.-Air cylinder 23 is attached to riser 20 through bracket 33. Opposite ends of cylinder 23 are connected through air hoses 34 and 35 to switch box 21 as further described below.

As seen from Figure 4, suction cup arm 22 rides on track 22a, which is supported by bracket 33' through extensions 33a.

Gear linkage.-As seen in Figures 2 and 3, suction cup 24 is attached to arm 22 through a linkage including elbow 36 and pin 37 on the end of arm 22, which are arranged in such a way as to permit rotation in at least one plane. Preferably elbow 36 is mounted for rotation in a vertical plane and also for rotation about pin 37 in a horizontal plane. For the latter rotation elbow 36 is attached at its end opposite suction cup 24 to a partial gear 38 rotatable about pin 37. At the front end of the cogs of gear 38, a triangular projection 38a extends from the circumference of the gear.

Gear 38 meshes with a fixed rack 39 so that when arm 22 is moved forward the gear is caused to rotate about pin 37, until arm 22 reaches a position in its movement so far forward that the cogs are no longer so meshed. When arm 22 reaches this forward position, projection 38a slides against the straight extension of rack 39, as shown in Figures 2 and 3, and causes suction cup 24 to move straight forward the remainder of the distance to the feeding station.

When arm 22 is moved backward from the feeding station, suction cup 24 first moves away in a straight line, then as gear 38 meshes in rack 39 it swings through an arc in the horizontal plane.

Switch box.--The operation of switch box 21 determines the direction in which the pistons in air cylinders 13 and 23 are actuated. Switch box 21 contains transwhenever main switch from the station former 40, air valves 41 and 42, and vacuum actuated switch 43.

has two sets of output contacts, only one of which can beclosed at any given time. One set is closed and the other opened at each end of the travel of piston 14 of air cylinder 13; Opposite air outlet openings of air valve 42 are connected through air hoses 34 and 35 to opposite ends of air cylinder 23. The opposite electrical input terminals of air valve 42 are connected to opposite output terminals of vacuum actuated switch 43.

1r pressure sourca-Air under pressure is provided from an external source through air hose 53. After passing though air valves 41 and 42, respectively, the air provides the actuating force in 23.

upon it by the restraining pressure of member 54.

livery of bag.-To prepare the ba openling machine for operation, switch 31 is closed t; supp y current to motor 27, and air ressur to air hose 5 p e is summed Motor 27 operates pump in vacuum lines and 48. 25 through suction cup 24.

26 to reduce the pressure s draws air into hose air cylinders 13 and So long as air is free to enter suction cup 24, the differential in pressure between the inside of hose 48 and atmospheric pressure is relatively slight. if the opening of suction cup 24 is blocked so that air from the outside may not sure in hose 48 will be further reduced by the action of pump 26.

Vacuum actuated switch 43 is so adjusted that a re duction in pressure in hose 34 and open air hose 35.

The air entering through hose 35 into air cylinder 23 at the forward This drives the piston in cylinder causes arm 22 to slide away from the feeding station. As seen in Figure 3, the backward motion of The inertia of the bag causes it to be slightly opened as it is swung in th' way to the delivery point. The opening of the bag is assisted by the restraining effect of element 54 as described above.

If it is desired to have additional assurance that the bag will open pulled away from the bag supply, the supply may be so arranged that the tops of the bags are tilted somewhat to the back. his may be done by by having a of the bag supply.

With such bag top to pull away somewhat from the side gripped by the suction cup.

Return of suction cup.When the bag is removed hose 53 under pressure is thus forced When microswitch 18 is opened by the arrival of a bag at the feeding station, electrical energy is no longer applied to reversing switch 46, so valve 41 is not actuated and air continues to pass through whichever one of lines 44 and 45 is open at the time. This forces the piston in cylinder 13 to complete the half cycle it is in at the moment and then to stop. In other words, the piston in cylinder 13, and also the rod 14, move into their highest position if line 45 is openand into their lowest if line 44 is open-and remain there so long as microswitch 18 is open.

When suction cup 24 has removed enough bags, switch 18 is closed again because there is no longer any pressure of a bag at the feeding station to keep it open. Reversing switch 46 is then energized, air valve 41 is actuated, and air flows from valve 41 through either air hose 44 or 45, depending upon the position which was occupied by the piston in cylinder 13 when cylinder 13 ceased operation at the end of its last half cycle. If the piston last came to rest in its lowest position because line 44 was then open, reversing switch to now acts to cause air valve 41 to block line 44 and open line 45. Thus, the piston is moved upward, and its cycle of operation continues as described above until microswitch 18 is opened again.

So long as piston rod 14 is moving up and down, pawl 16 is moved down and up continuously by arm 15, there by imparting a counterclockwise motion to ratchet wheel 17 as seen at the left of Figure 1. This causes pulley wheels 8 to rotate, and conveyor belts 9 to move forward to the feeding station, until a bag is brought forward far enough that it presses against microswitch 18 to open that switch.

In a somewhat similar manner, guide chains 11a move the tops of the bags forward to the feeding station, until a bag is brought forward far enough that it presses against microswitch 126 to open that switch and cease actuation of motor 12.

The first bag presented at the feeding station is then gripped by suction cup 24, moved away, and presented at the delivery point.

The above detailed description of this invention is given for clearness of understanding only. No unnecessary limitations should be understood therefrom, as modifications will be obvious to those skilled in the art.

We claim:

1. In a machine for opening flat folded bags from a stack of such bags, a bag conveyor comprising a frame supporting carrying means which frictionally engages the edges of a stack of fiat folded bags and delivers said bags to a pick-up station, switch means for automatically stopping the conveyor when the forwardmost bag reaches the pick-up station, a member having a suction cup mounted at one end and the other end of the member communicating with a reciprocating piston in a cylinder, said piston forming a hermetic barrier in the cylinder, fluid lines communicating with each side of the piston, and automatic means to selectively supply fluid pressure through said lines first to one side of the piston to move the suction cup to the pick-up station and into engagement with one face of the forwardmost bag and secondly to the other side of the piston to move the suction cup and engaged bag away from said pick-up station.

2. A machine as defined in claim 1 in which a suction line, separate from the fluid lines, communicates with the suction cup.

3. A machine as defined in claim 1 having a suction line communicating with the suction cup and control means responsive to the degree of suction in the suction line between the suction therein when the cup is engaged with a bag face and when the cup is open, said control means activating and controlling the automatic valve means to create the differential pressure in the cylinder.

4. An apparatus for conveying stacked bags to, and replacing bags removed from, a pick-up station, comprising a conveyor support frame, an endless belt supported by the frame for carrying bags to the pick-up station with the stacked bag edges in contact with said belt, pulley means communicating with the belt to drive it, crank means on said pulley means, a gas cylinder having a piston therein, a piston rod connected at one end to said piston and connected at the other end to the crank means by connecting means which convert rectilinear motion of the piston rod into circular movement of the crank means, switch means at the pick-up station closed when bags are not at the station and open when bags are at the station, and gas pressure means responsive to the switch means for creating differential gas pressure in the cylinder on each side of the piston thereby actuating the piston rod to move the pulley driving the belt supporting the bags.

5. In a machine for opening flat folded bags from a stack of such bags, means for conveying a stack of flat folded bags to a pick-up station, a member having a suction cup mounted at one end for engaging said bags at said station, the other end of said member communicating with a reciprocating piston in a cylinder, said piston forming a hermetic barrier in the cylinder, fluid lines communicating with each side of the piston, a suction line separate from the fluid lines communicating with the suction cup, and automatic valve means to selectively supply differential fluid pressure through said fluid lines to one side of the piston to move the suction cup to the pick-up station and into engagement with one face of a bag and to the other side of the piston to move the suction cup and engaged bag away from said pick-up station.

6. In a machine for opening flat folded bags from a stack of such bags, means for conveying a stack of fiat folded bags to a pick-up station, a member having a suction cup mounted at one end for engaging said bags at said station, the other end of said member communicating with a reciprocating piston in a cylinder, said member having means for angular movement of the suction cup relative to the piston to deliver an engaged bag facing in another direction when moved away from said station, said piston forming a hermetic barrier in the cylinder, fluid lines communicating with each side of the piston, and automatic valve means to selectively supply differential fluid pressure through said fluid lines to one side of the piston to move the suction cup to the pick-up station and into engagement with one face of a bag and to the other side of the piston to move the suction cup and engaged bag away from said pick-up station.

7. In a machine for opening flat folded bags from a stack of such bags, means for conveying a stack of. flat folded bags to a pick-up station, a member having a suction cup mounted at one end for engaging said bags at said station, the other end of said member communicating with a reciprocating piston in a cylinder, said piston forming a hermetic barrier in the cylinder, a suction line communicating with the suction cup, control means responsive to the degree of suction in the suction line between the suction therein when the cup is engaged with a bag face and when the cup is open, fluid lines communicating with each side of the piston, and automatic valve means to selectively supply differential fluid pressure through said fluid lines to one side of the piston to move the suction cup to the pick-up station and into engagement with one face of a bag and to the other side of the piston to move the suction cup and engaged bag away from said pick-up station, said control means activating and controlling the automatic valve means to create the differential pressure in the cylinder.

8. A machine as defined in claim 3 in which gas means are provided for supplying gas under superatmospheric pressure to the cylinder through the fluid lines.

9. A machine as defined in claim 3 in which said member communicating with the piston and suction cup has means for angular movement of the suction cup to deliver an engaged bag facing in another direction when moved away from said station.

10. In a machine for opening fiat folded bags from a stack of such bags, means for conveying a stack of flat folded bags to a pick-up station, a member having a suction cup mounted at one end for engaging said bags at said station, the other end of said member communicating with a reciprocating piston in a cylinder, said piston forming a hermetic barrier in the cylinder; fluid lines communicating with each side of the piston, automatic valve means to selectively supply differential fluid pressurethrough said lines to one side of the piston to move the suction cup to the ick-up station and into engagement with one faceof a bag and to the other side of the piston to move the suction cup and engaged bag away from said pick-up station, and restraining means to partially restrain movement of the bag engaged by the suction cup away from the pick-up station, said restraining means comprising a first guide member pressing the edges of the bag at the pick-up station and of the bags in the stack immediately adjacent thereto and a "8 second guide member pressing the edges of-a group of bags in the stack back from the bags at the pick-up station, said first and second guide members each pressing the edges of common bags away from the pick-up station.

References Cited in the file of this patent UNlTED STATES PATENTS 1,589,800 Frank June 22, 1926 1,600,320 Danquigney Sept. 21, 1926 1,919,060 Harder July 18, 1933 1,942,885 Tevander Jan. 9, 1934 2,076,186 Reynolds et a1. Apr. 6, 1937 2,138,306 Patrick Nov. 29, 1938 2,420,763 Wells May 20, 1947 2,449,690 Chapman Sept. 21, 1948 2,528,997 Blanchard Nov. 7, 1950 2,546,193 Lindstaedt et al. Mar. 27, 1951 2,554,579 Lautfer May 29, 1951 2,684,848, Pearce July 27, 1954 2,725,168 Lindstaedt et al. Nov. 29, 1955 FOREIGN PATENTS 293,786 Great Britain May 23, 1929 515,729 Germany Jan. 12, 1931 

